Global warming? Maybe. But give some credit to the big balding guy in the dark threads sitting at his usual booth halfway back at Morty’s Deli.

That’s Dan E. Moldea, one of the premier investigative reporters of his generation. Books on Hoffa, on the killing of RFK, on the mob and pro football, on the mob and Ronald Reagan, on OJ, on Vince Foster.

Name doesn’t ring a bell? Think Larry Flynt and Sen. David Vitter, R-La. It was Moldea, working for Flynt, who on July 6 found Vitter’s number in the phone records of the so-called D.C. Madam, just as it was Moldea, working for Flynt, who amid the impeachment of Bill Clinton found a former mistress of Rep. Bob Livingston, R-La., aborting his rise to speaker of the House and, Moldea believes, saving the Clinton presidency.

“This is just the beginning; I view Vitter as a shot across the bow,” says Moldea of his renewed collaboration with Flynt, precipitated, he says, by word of a new anti-Clinton “smear campaign” in the works targeting Bill Clinton’s post-presidential behavior. “If these guys want a showdown on the issue of morality, by God we’re going to give it to them.”

Moldea, 57, is a cool customer, a noirish figure in a black and white world; the shadowy guy who knows where the bodies are buried (or not buried, as in the case of Hoffa, who he believes was “crushed and smelted”). But, over the course of a recent nearly five-hour interview at Morty’s in upper Northwest Washington, the secret of Moldea’s double life spills out.

“I got a reputation as a tough guy, but,” and here his voice tumbles to a hush, “I really am a nice person. But I can’t let that get around because people will f— with me. That’s what happens in this business.”

There it is. Dan Moldea, Larry Flynt’s shamus of shame, is a sentimental sweetheart, a gentle soul, generous friend and notorious over-tipper. In a world of self-promoting bravado, he is self-deprecating to the last, while allowing, “I usually have good intentions.”

He won’t allow a photograph to be taken of him, or provide a photograph, for this story. He’s stayed off TV lately. He doesn’t want to appear to be grabbing glory off other people’s misery. “It may seem an ironic term for me to use, but I think it would be the epitome of bad taste.”

“Dan is one of the truly decent people in this world,” says his lawyer, Roger Simmons, who represented Moldea in his quixotic libel suit against The New York Times in the early 1990s for a negative book review that misrepresented what he wrote.

“In some ways he’s a tough guy, but in another way he’s just a big teddy bear,” says Deborah Jeane Palfrey, the D.C. Madam who has been indicted on federal racketeering charges, talking by telephone from her California home. Moldea and Palfrey are shopping a book proposal, and on July 13, Moldea threw a party at Morty’s to introduce her to some of his journalist pals.

Now, when Palfrey thinks of Moldea, “I think of matzo ball soup.”

“He has this kind of noble grandeur that is gone from the world,” says Laurence Leamer, a close friend who has written books on the Kennedys and on Arnold Schwarzenegger.

But does Larry Flynt really merit a knight-errant?

“Larry Flynt’s a total sleazebag,” says Leamer, but he maintains Moldea’s purpose is pure.

Moldea, who says he has never seen Flynt’s Hustler magazine, knows he will always be guilty by association. But he thinks Flynt has been on the side of the angels in his campaign to expose the sexual hypocrites of the Republican right.

“I’d sell apples on a street corner to go after these guys,” says Moldea. “That’s the thing, I’ve started to view right-wing Republicans as the new organized crime.”

“Dan reminds me of Gary Cooper in `High Noon’ _ the quiet, tough-as-nails professional who believes he should uphold the honor and law of the badge he swore to wear,” says James Grady, author of the book on which the film “Three Days of the Condor” was based, who has known Moldea since Grady worked as an investigator for columnist Jack Anderson. “For Dan, the badge is investigative reporting, muckraking at its best, and the oath is the idea that if you dig up the truth, people in a democracy will care and good things can happen.”

Grady believes that next to Seymour Hersh, Moldea is the top investigative reporter of his time. “He should be one of those name-brand journalists, but he’s not very comfortable in that role.”

Not everyone is a fan.

“He is to journalistic integrity what Bill Clinton is to marital fidelity,” says Mark R. Levin, president of the conservative Landmark Legal Foundation (Landmark has nominated Rush Limbaugh for the Nobel Peace Prize). In 1999 Landmark filed a complaint with the Justice Department accusing Flynt and Moldea of trying to obstruct the Clinton impeachment inquiry.

But Moldea has a reputation as a scrupulous reporter. He has never been sued for any of his books. He worked years on a book based on his belief that there was a conspiracy to kill Robert F. Kennedy, but reversed course when he became convinced that Sirhan Sirhan acted alone. With Flynt, he says, “We can’t make any mistakes.”

Never married, he has been going out with the same woman for nearly 20 years, though they don’t live together. “She doesn’t like me much.”

No children. “I don’t think I would have been a very good father.”

And the future? “I have this fear I’m going to end up with a shopping bag in Dupont Circle, screaming at myself.”

Moldea was born in Akron, Ohio. His religion is Eastern Orthodox; his ancestry Romanian. He has always been a liberal, but one with a weakness for cops and wiretaps. At the left-wing Institute for Policy Studies in Washington, where he has been affiliated over the years, “they called me the resident thug.”

But, he says, what really radicalized him was when Regnery, a conservative publisher, asked him in 1997 to write a book about the death of Vince Foster. Foster, Bill Clinton’s childhood friend and deputy White House counsel, was found dead in Fort Marcy Park just outside Washington in 1993, an apparent suicide. Many in the conservative media saw foul play, but Moldea found “instead of the Clintons being involved in some grand conspiracy to either murder Vince Foster or cover up the circumstances of his death, that in fact it was a conspiracy among certain right-wing journalists to make it look that way.”

The experience primed Moldea to accept Flynt’s invitation in the fall of 1998 to help him expose the sexual affairs of the anti-Clinton posse.

The payoff came when Livingston announced, as the House was voting to impeach Clinton, that he would not stand for speaker. Moldea trembled. “I thought we had destroyed the country.” But he came to believe they had saved the Clinton presidency. “When we got Bob Livingston, I think we derailed the train to remove Clinton from office.”

A few months ago, Moldea says, he learned from an “impeccable” source that “an unnamed group of former intelligence officers have done an opposition research campaign against Bill Clinton, which is tantamount to a smear campaign, which concentrates on his activities since he left the White House. This is coming out, and that’s when I said, `We’ve got to get back to work.”’

“Who knows when they are going to pull the trigger on this, but we’re going to unleash hell when that happens,” he says.

“I don’t know if Hillary is Larry’s candidate, but she’s certainly mine,” says Moldea, though he knows that the Clintons, as in the past, will want nothing to do with him or Flynt.

Meanwhile, Palfrey thinks she and Moldea are the answer to each other’s prayers. “This is not a Mayflower Madam book, not a Heidi Fleiss book. This is a very serious book about corruption and politics,” she says. “I want him to dig, dig, dig and find out what’s really going on.”

And when Moldea does, she says, “the man is going to be legend,” finding a mass audience at last.